The state of development of personal or office information processing applications makes manifest an increasingly frequent need to manipulate data that must in some cases remain confidential. The data in such systems are generally stored on highly vulnerable media, such as memories, diskettes, magnetic tape, or even hard disks.
To lend the data a certain confidentiality, protecting them with the aid of passwords has already been proposed. The principle of this is as follows: A user can access an application involving particular data only by using a password, that is, by introducing a succession of alphabetical or numerical or alphanumeric terms with the aid of a keyboard or any other suitable input means. Such a method is not especially reliable, because methods for making it possible for recovering the password, or even circumventing it, exist which makes "pirating" of the application relatively easy.
Another method of protection consists in removing the medium containing the data physically at the end of each application in question. This assumes extreme rigor on the part of the user, and can be considered only if the medium containing the data is removable--which a priori precludes the case in which the data are on the hard disk--and if the medium can be locked up in a secure location after having been removed. Additionally, this is not truly practical unless furthermore, only a single user is capable of manipulating the data in question.
The problem of data protection is accordingly crucial. This is all the more true as lightweight portable computers, which can easily be transported to do work, in particular while traveling, become increasingly more widely used. It is in fact not a rare occurrence by now to see persons using such a machine at the offices of a client, to save time during a transaction or a negotiation. In the absence, however brief, of the user, third parties can profit from the situation by attempting to pierce some of the secrets of the machine, particularly the secrets of the files incorporated in the machine.
The disadvantages of earlier methods have been overcome by proposing the use of memory and/or microcomputer cards, also known as "smart cards" like those described in French Patents 2,401,459 and 2,337,381, corresponding to respective U.S. Pat. Nos. 4,211,919 and 4,222,516, in order to provide extremely certain control of the rights of the user or to protect the files. The subject matter of U.S. Pat. Nos. 4,211,919 and 4,222,516 is hereby incorporated herein by reference. The card, or an equivalent portable medium, contains an electronic memory, with secret data, for instance, which are used in processes of verification of the rights of the bearer, or again in processes of memorizing or encoding/decoding of the data to be protected.
Verification or security methods that employ portable articles, such as memory and/or microcomputer cards, are numerous and are not the subject of the present invention. Some control the rights of the bearer by encoding the data to be protected. Others prohibit starting an application unless the card has not been read and the data it includes have been combined with the data to be protected. This latter method is the subject of French Patent 2,523,745, corresponding to U.S. Pat. No. 4,683,553, and provides for associating a memory and/or microcomputer card with applications software. The card contains the information necessary for starting the software and prior dialog between the card and the processing apparatus is necessary. Without it, the applications software cannot be employed.
It should be noted that depending on the degree of security required, a memory and/or microcomputer card or equivalent article, because of its great flexibility of use, makes it possible to use one or another of the methods mentioned, or to combine all or some of these methods.
Consequently, a memory and/or microcomputer card or any equivalent medium makes highly secure information processing applications possible.
However, when one seeks to use a portable article in connection with a computer, a specialized external reader, connected by way of an available interface on the processing machine, must be used. In certain computers, for example, the specialized reader is connected to the machine by a standard V24 or RS232 interface. Aside from its cost and its bulk, a reader of this kind accordingly occupies one output of the machine, which then is unavailable for other purposes. Hence connecting the reader can prevent connecting some other useful resource or peripheral, such as a printer, telephone line, or network.
To overcome these disadvantages, some manufacturers have proposed incorporating the reader in the machine, so that it does not occupy an output of the machine. However, this provision can be considered only if it has been provided for in the design of the machine, because physical interfaces and the slot for the reader must be provided. A reader must accordingly be adapted to a given type of machine, which is not ideal, particularly if the machine is a sophisticated one.
A solution consists in providing an additional output for a reader of cards or equivalent portable articles. This, however, would also require modification of the physical interfaces, which is not cost effective, because the security device is generally used only for a limited period at the time an application is started or finished. Hence its time in use is extremely short compared with the time the machine is used. Moreover, some users have no need for such a device and would not want to bear the additional cost entailed in providing for the existence of this output.
Accordingly, a first object of the invention is to overcome all the disadvantages in terms of connection or location, while using a security device that employs at least one memory and/or microcomputer, so as to preserve the advantages and potentials of such a device.
Moreover, a second object of the invention is to achieve a device capable of being easily connected, at low cost, to all types of mutually compatible machines, without requiring modification of the existing physical interfaces.
A third object of the invention is to preserve the portable aspect of the security device, so that, if a user does not want to travel with his own computer, the user can carry the security device with him, as he does a memory and/or microcomputer card or equivalent medium, and yet still preserves the security of the applications he uses, wherever he may be, by connecting the security device to the machine he uses.
A data processing machine, such as an office or personal computer, includes a central processing unit and associated peripherals. The central processing unit includes a processor and data (RAM) or program (ROM) memories necessary for its function. The peripherals either make it possible to keep a record of the processing done (mass memories, hard disks, diskettes, tape), or enable dialog between the user and the machine (keyboard, screen, printer) or between the machine and the external environment (input/output connectors). Depending on the configuration, some peripherals may be incorporated physically in the same block as the central processing unit. Hence a portable computer, for instance, will have a keyboard, screen, central processing unit, and optionally a hard disk or diskette reader, and a modem in the same block. In other configurations, in a manner known per se, the central processing unit is physically separate from all or some of the peripherals. In that case, the central processing unit then includes interface circuits connected to the specific input/output connectors for each additional peripheral that may be connected to the machine.